It's been my experience that carry on size rules are not enforced. This past Friday, I rode #14 LAX -> PDX and the family in the family room brought on a 'monster' roll on <what I thought was> a suitcase. I asked the woman about it's unusually large size (perhaps 50% bigger than any rolling suitcase I've ever seen! It was about the size of a 1920s steamship trunk!) as the lower area of the baggage 'rack' already had a couple of large suitcases in it, the 'monster' was left in the aisle in front of the baggage area, pretty much blocking everyone from getting past it to the stairwell. I always request roomette #14, so I got a ringside seat on the action. She said it was an oversize stroller for her kids. I think she had a toddler and a 3 year old. Fortunately, the attendant removed the big luggage from the lower part of the rack and rolled the stroller in. I think there was enough room to fit an airline-size carry on alongside the monster, but don't hold me to it.
Even on the NEC, I've never seen anyone be 'challenged' by a conductor or even another passenger about the size of a carry on. So, it's nearly commonplace that someone will bring on the largest rolling suitcase made and fortunately, find (or be directed to) the large luggage storage area in the car. Unfortunately, when it's a 4-wheeler piece of luggage, it rolls out into the aisle at every left turn and back when turning right.
It should be noted that Viewliner sleepers have NO baggage storage area other than the above the aisle 'cubby hole' in each room. As a result, I've witnessed the sleeper attendants tell the passenger to go back to the station and get it checked. I've also seen extra large suitcases in the shower! When that has happened, I simply roll the case into the aisle when I shower in the early AM (5:30ish) and roll it back when I'm done.
Edited by bratkinson, 25 April 2018 - 10:50 PM.